feat: 新增APP启动页功能，完善多项业务优化

zjk

2026-09-24 4c4b36e7337385ff15ff66a0ad487cdffaf9c86b

 tcm-training-admin-backend/src/main/java/com/tcm/training/admin/system/entity/SystemSettings.java

@@ -33,6 +33,12 @@
    @TableField("member_expire_remind_days")
    private Integer memberExpireRemindDays;

    @TableField("startup_page_enabled")
    private Boolean startupPageEnabled;

    @TableField("startup_page_image_url")
    private String startupPageImageUrl;

    @TableLogic
    private Integer deleted;